Correlates of Male Consortship Rate in Free-Ranging Rhesus Macaques (Macaca mulatta)

Male–male competition for access to receptive females can take the form of nonrecurring fights and/or a sustained contest over mating opportunities. Male physical condition has been linked to dominance rank and reproductive success in species characterized by intrasexual fights for dominance and access to females. In group-living species characterized by endurance rivalry, however, factors contributing to male reproductive success are less well understood. In such species, particularly seasonally breeding ones with low sexual dimorphism and seniority-based rank, age and social factors other than rank may prove important. In the absence of genetic data, male mate guarding or consortship can serve as an indicator of male reproductive success. To evaluate the contribution of age and intragroup sociality to male consortship rate, I collected behavioral data during one nonmating and one mating season in two social groups of free-ranging rhesus macaques that experience no predation or food scarcity. Higher-ranking males, younger males, or males that exhibited lower rate of intrasexual aggression had higher consortship rates. Male–female dyads that groomed outside consortship did not form consortships as often as dyads that did not engage in nonconsort grooming. This is the first study to identify the significance of male–male aggression and male–female affiliation to male consortship rate in a species characterized by endurance rivalry, high male rank stability, and strong female mate choice. Social behaviors and male age may be particularly important in determining male reproductive success in populations experiencing high food availability and a lack of predation, which are typical of an increasing number of vertebrates in areas densely populated by humans.     

Social relationships between adult male and female rhesus macaques: 1. Sexual consortships

The sexual relationships of 15 adult male rhesus macaques (Macaca mulatta), of one social group in the Cayo Santiago colony, Puerto Rico, were studied during the 1981 mating season. Two criteria were used to determine whether or not a focal male was in consort in a given 20-min observational sample. One hundred and thirty-two consortships were recorded. The distribution and duration of all consortships, and the distribution of those consortships that coincided with the estimated time of conception, were positively correlated with male dominance rank and length of tenure. Correlations with dominance were stronger than those with tenure. Older females had more consortships with focal males than younger females. There was no relationship between female rank and the distribution of consortships. Consortships did not give exclusive access to receptive females although they may do in feral situations. Males were primarily responsible for maintaining proximity in about two thirds of consortships. The four top-ranking males were primarily responsible in all but one of their consortships. Almost all of those in which the female was primarily responsible involved younger, slightly lower-ranking males. This pattern may have resulted from the females being attracted to the latter males although other interpretations are possible. The partner who was primarily responsible for maintaining proximity also tended to be the predominant groomer, supporting the view that grooming plays a role in the maintenance of sexual consortships. Almost a third of consortships were with females who had conceived, suggesting that males could not accurately assess female reproductive state. Consortships maintained by the male were longer than those maintained by the female. Males may try to increase their chances of fertilising a female by prolonging the consortship. High-ranking males may have been more successful at this, resulting in the positive correlation between male dominance rank and consortship duration.     

Behavioral and physiological plasticity: Rapid changes during social ascent in an African cichlid fish

In many vertebrates, reproduction is regulated by social interactions in which dominant males control access to females and food. Subordinate males that displace dominant individuals must rapidly adopt behavioral and physiological traits of the higher rank to gain reproductive success. To understand the process of phenotypic plasticity during social ascent, we analyzed the temporal expression pattern of dominance behaviors and circulating androgen levels when socially-suppressed males of an African cichlid fish Astatotilapia burtoni ascended in status. These experiments tested a prediction of the ‘challenge hypothesis’ that, during periods of social instability, male androgen levels are higher than during socially stable times. We found that socially and reproductively suppressed males perform territorial and reproductive behaviors within minutes of an opportunity to ascend in status, and that animals switch from initial expression of territorial behaviors to more reproductive behaviors during territory establishment. Following this rapid response, social stability may be achieved within 1-3 days of social ascent. Consistent with predictions of the ‘challenge hypothesis’, circulating 11-ketotestosterone (11-KT) levels were elevated within 30 min following social opportunity, coincident with increased aggressive behavior. However, territorial behaviors and serum 11-KT levels were then dissociated by 72 h after social ascent, suggesting either rapid social stability and/or increased physiological potential for androgen production. This behavioral and physiological plasticity in male A. burtoni suggests that perception of social opportunity triggers a suite of quick changes to facilitate rapid transition towards reproductive success, and reveals important features of social ascent not previously recognized.     

Urinary C-peptide levels in male bonobos (Pan paniscus) are related to party size and rank but not to mate competition

Within- and between-species variation in male mating strategies has been attributed to a multitude of factors including male competitive ability and the distribution of fertile females across space and time. Differences in energy balance across and within males allow for the identification of some of the trade-offs associated with certain social and mating strategies. Bonobos live in groups with a high degree of fission–fusion dynamics, there is co-dominance between the sexes and a linear dominance hierarchy among males. Males compete over access to females, breeding is aseasonal, and females exhibit sexual swellings over extended time periods. In this study we use urinary C-peptide (UCP) levels in male bonobos (Pan paniscus) obtained from 260 urine samples from a wild bonobo community, to quantify male energy balance during mate competition and levels of gregariousness in the species. Although high ranking males are more aggressive, spend more time in proximity to maximally tumescent females, and have higher mating frequencies, we found no indication that mate guarding or mate competition affected male energy balance. Our results showed a positive correlation between monthly mean UCP levels and mean party size. When traveling in large parties, high ranking males had higher UCP levels than those of the low ranking males. These results support the hypothesis that patterns of fission–fusion dynamics in bonobos are either linked to energy availability in the environment or to the energetic costs of foraging. The finding of a rank-bias in UCP levels in larger parties could also reflect an increase in contest competition among males over access to food.     

“Following,” an Alternative Mating Strategy Used by Male Olive Baboons (Papio hamadryas anubis): Quantitative Behavioral and Functional Description

Recent data reveal that high-ranking males are unable to monopolize sexual access to fertile females, suggesting the potential evolutionary significance of alternative strategies across many taxa. We examined a well known behavior, “following” of a consortship by adult male olive baboons (Papio hamadryas anubis), that has received little empirical attention. Four consort takeover tactics have been suggested, for both follower and nonfollower males: takeover of an abandoned consort female, individual aggressive challenge to oust the consort male, coalitionary challenge to oust the consort male, or an opportunistic consort takeover relying on the consort male being distracted. We addressed the following questions: 1) How does the behavior of followers differ from nonfollowers? 2) Is following an effective alternative mating strategy? 3) What tactics do followers use to obtain access to fertile females? 4) Do dominance rank and female cycle day influence tactic expression? We studied two habituated groups of olive baboons from September 2009 to July 2010 in Kenya. Followers had a higher rate of agonistic interactions with the consort male and affiliative interactions with other followers. Overall, 74% of consort takeovers were executed by follower males of the targeted consortships. Each of the four consort takeover tactics were used by both follower and nonfollower males, although followers used the individual aggressive challenge and coalitionary challenge tactics more often than nonfollowers. Dominance rank, but not female cycle day, influenced the expression of consort takeover tactics. Our findings indicate that following provides males with sexual access to females.     

Social correlates of testosterone and ornamentation in male mandrills

We investigated relationships between fecal androgen concentrations, facial coloration and behaviour in semi-free-ranging male mandrills. We found that fecal androgen levels were significantly positively related to dominance rank, independent of rank stability and the mating period, suggesting that male mandrills live in a permanently aggressive context in which they must actively maintain their dominance status. Facial red coloration was also significantly related to both fecal androgen levels and rank, with high ranking males having both higher androgen levels and redder faces, although dominant males did not always have the highest androgen levels or the reddest faces. Predictive relationships between androgen levels, coloration and rank were short-term. Androgen concentrations and facial redness both increased in the presence of receptive females, as did the former during periods of rank instability. We conclude that male facial redness is likely to represent an honest signal (to other males) of current androgen status, competitive ability and willingness to engage in fights and that females may also use this to assess male condition. Further, our findings provide support for the “challenge hypothesis” as originally proposed for birds by Wingfield.     

Influences of female partner preference on potential reproductive outcome in Japanese macaques.

The immediate effects of female partner preference on male mating behaviors and its potential influence on male reproductive success and conception in the Japanese macaque (Macaca fuscata) were analyzed. Although male dominance interactions probably led to low-ranking males having more single-day consortships and high-ranking males more multi-day consortships, dominant males were unable to prevent females from mating with preferred subordinate males. Ultimately, there was no marked difference in the number of estimated offspring sired. Females chose not to mate with certain males and actively mated with others, suggesting that female partner preferences do affect conception. Evidence for this was found in paternity estimates, which reflected observed preferences for particular middle-ranking young adult males.     

Concealed fertility and extended female sexuality in a non-human primate (Macaca assamensis)

In numerous primates living in mixed-sex groups, females display probabilistic cues of fertility to simultaneously concentrate paternity to dominant males while diluting it amongst others as a means to reduce the risk of infanticide and to increase male care for offspring. A few species, however, lack these cues and potentially conceal fertility from males; yet, to date, little is known about mating patterns and their underlying proximate mechanisms in such species. Here, we investigated mating activity and sexual consortships relative to female reproductive state in wild Assamese macaques (Macaca assamensis), a species where females lack prominent anogenital swellings and copulation calls. During two mating seasons (2837 contact hours) we recorded sexual and social behaviors, sexual consortships, and collected 1178 fecal samples (n = 15 females) which were analyzed for progestogen concentrations to assess female reproductive state and to determine the timing of ovulation and conception. Although mostly conceiving in their first ovarian cycle, females were sexually receptive throughout the entire 4-month mating season, and within-cycle mating frequencies were not increased during fertile phases. Dominant males did not monopolize fertile matings, and consortships by high-ranking males lasted for long periods, which were not exclusively linked to female fertile phases. Furthermore, females copulated promiscuously but not randomly, i.e. for almost every female, matings were concentrated to a certain male, irrespective of male rank. Collectively, we demonstrate that fertility is undisclosed to males. The extreme extended female sexuality facilitated by concealed fertility may allow females to create differentiated mating relationships within a promiscuous mating system. Our study provides important new insight into the plasticity of female sexuality in non-human primates.     

Male Mating Tactics in Captive Rhesus Macaques (Macaca mulatta): The Influence of Dominance, Markets, and Relationship Quality

Male mating success in a multimale–multifemale group can depend on several variables: body condition, dominance, coalitions, “friendship,” or an exchange of services for mating access. Exchange patterns may also be determined by market effects or social relationships. We studied the mating tactics of males in a captive, multimale–multifemale group of rhesus macaques and the resulting patterns of mating and paternity to determine the influence of dominance rank, mating markets, and relationship quality on their mating tactics. Male rank was positively related to the total number of copulations and the number of mating partners, but did not explain male mating distribution completely. Moreover, male fertilization success was not related to male rank. Males did not exchange grooming for mating access on the same day and neither the supply nor the rank (as a proxy for quality) of receptive females affected the amount of male grooming, suggesting that market effects did not explain male mating access. However, there was a positive correlation between long-term grooming patterns of both males and females and mating access, indicating that social relationships were important for male mating access. Paternity data revealed that these social relationships were also important for male reproductive success. We conclude that both male rank and male–female “friendship” determined male mating access in these rhesus macaques, but that “friendship” was more important in determining paternity, emphasizing the importance of intersex social bonds in male mating success in multimale primate societies.     

Determinants of male mating success in a large group of Barbary macaques (Macaca sylvanus) at Affenberg Salem

Male mating activities in relation to the likelihood of ovulation and conception were studied in a large group of semifree-ranging Barbary macaques (Macaca sylvanus) during two successive mating seasons. In both mating seasons, adult males attained a significantly higher mating success than subadult males, and they monopolized high ranking females more effectively than low ranking females during the period when conception was most probable. Also, in both mating seasons male rank was significantly correlated with male mating success if all sexually mature males were included. Nevertheless, mating success was not a linear function of age or rank. In both mating seasons mating success of 5-year-old males was much higher than that of dominant but peripheralized 6- and 7-year-old males. Moreover, a significant correlation between rank and measures of mating success among adult males was found in the second but not in the first mating season. The results indicate that mating and, most probably, reproductive success of male Barbary macaques is dependent on the male's social position in the group, which is defined not only by the outcome of dyadic agonistic encounters but also by the ability to get a central position in the group, and on the stability of rank relations.     

Relationship between sexual interactions and the timing of the fertile phase in captive female Japanese macaques (Macaca fuscata)

Japanese macaques live in multi‐male/multi‐female social groups in which competition between males, female mate choice, and alternative male mating strategies are important determinants of mating and reproductive success. However, the extent to which adult males rely on female behavior to make their mating decisions as well as the effect of social rank on mating success are not clear as results are inconclusive, varying from study to study. In this study, we combined behavioral and endocrine data of 14 female Japanese macaques to examine the relationship between ovarian cycle phase and frequency of sexual behaviors, and to investigate how social rank influences sexual behavior in this species. We found that there was no increase in female proceptive behaviors during the fertile phase of the ovarian cycle, suggesting that female behaviors did not clearly signal the probability of conception. In spite of that, the frequencies of ejaculatory copulations were highest during this phase, indicating that the attractivity of females increased significantly during the period with higher probability of conception. Males, and especially the highest ranking male, were able to discriminate females nearing ovulation and to concentrate their mating effort, implying that the timing of ovulation was not concealed from them. The α male seemed able to monopolize most female matings, which is probably due in part to the low number of females simultaneously ovulating and to the limited number of inconspicuous places that the lower ranking males have to mate with females and avoid α male aggression. All together, these results suggest that different males may have access to different signals of ovulation and/or are differentially restrained as to how they can act on that information. The exact nature of the estrogen‐related cues males use to recognize female reproductive status, and to what extent males use them warrants further investigation. Am. J. Primatol. 71:868–879, 2009. © 2009 Wiley‐Liss, Inc.     

Social behavior, foraging strategies, and fecal glucocorticoids in female blue monkeys (Cercopithecus mitis): potential fitness benefits of high rank in a forest guenon

Socioecological theory predicts that aggressive feeding competition is associated with linear dominance hierarchies and reproductive advantages for high-ranking females. Female blue monkeys contest fruits and have a linear dominance hierarchy, yet previous research has shown no evidence that high-ranking females benefit from greater feeding success or fertility. Here, we assess whether individuals differ in fecal glucocorticoid (fGC) excretion and examine proximate determinants of such differences to infer potential fitness correlates of rank, using data collected from two study groups in the Kakamega Forest, Kenya. We found that higher ranking females had preferential access to fruits in both groups, although the behavioral mechanisms leading to this effect varied between groups. Despite a consistent rank difference in feeding on fruits, an overall rank effect on fGCs emerged in only one group; females of this group spent comparatively more time feeding on fruits, fruits accounted for a greater proportion of the diet, and females engaged in more frequent food-related agonism. In addition, more females in this group were lactating during a period of low fruit availability, when rank effects on fGCs were particularly strong. Regardless of fruit availability, among lactating females of both groups higher rank was associated with lower fGC levels, indicating lower energetic stress in higher ranking females when energy demands were particularly high. Individual rates of agonism, a potential psychological stressor, were unrelated to fGCs at all times. After we accounted for rates of agonism and feeding on fruits, females of one group who groomed others more had lower fGCs, suggesting that variable social coping behavior can contribute to fGC variation in some groups. This study provides the first empirical evidence that high-ranking female blue monkeys may obtain fitness benefits from their social status, by gaining priority of access to fruits during critical times in the reproductive cycle.     

Mechanisms of sexual selection: sexual swellings and estrogen concentrations as fertility indicators and cues for male consort decisions in wild baboons

Male mate-guarding episodes ('consortships'), are taxonomically widespread, yet costly to individual males. Consequently, males should bias consortships toward females with whom the probability of conception is high. We combined data on consortships with visual scoring of sexual swellings and assays of fecal estrogen concentrations (fE) in a wild population of baboons (Papio cynocephalus) to test the hypotheses that sexual swellings are reliable indicators of (1) within-cycle timing of ovulation, (2) differences in conception probability among females that differ in maturational stage, and (3) conceptive versus non-conceptive cycles of parous females. We also evaluated whether adult males might rely on swellings or other estrogen-dependent signals (e.g., fE) for mate-guarding decisions. We found that sexual swellings reflected conception probability within and among cycles. Adult males limited their consortships to the turgescent phase of cycles, and consorted more with adult females than with newly cycling adolescents. The highest ranking (alpha) males discriminated more than did males of other ranks; they (1) limited their consortships to the 5-day peri-ovulatory period, (2) consorted more with adult than with adolescent females, and (3) consorted more with adult females on conceptive cycles than on non-conceptive cycles, all to a greater extent than did males of other ranks. Male mate choice based on sexual swellings and other estrogenic cues of fertility may result in sexual selection on these female traits and enhance dominance-based reproductive skew in males. Alpha males are the least constrained in their mating behavior and can best take advantage of these cues to mate selectively.     

Female behavioral strategies during consortship in Tibetan macaques (Macaca thibetana)

Consortship has been defined as a temporary association between an adult male and an estrous/receptive female. It has been considered as male mating strategies to improve male mating success and potential reproductive success. However, the female roles have been more or less neglected, and thus, less is known about female behavioral strategies during the consortship periods. In this study, during the two consecutive mating seasons, we collected behavioral data of free‐ranging Tibetan macaques (Macaca thibetana) habituated in Mt. Huangshan, China, to investigate female behaviors when she was consorted by an adult male. The results showed that (a) females were more likely to approach and exhibit sexual solicitation to their consorting males during the consorted period, and females also exhibited less approach to their nonconsorting males; (b) females exhibited strong responses (either departed distantly or formed affiliative relationships with their consorting male partner) when their consorting males mated with rival females or showed sexual motivation toward rival females; (c) female preferences were positively correlated to the duration of consortships and the frequencies of ejaculation copulations, independent of the social ranks of their consorting male partners. Our results suggested that female strategies played much more important roles in forming and maintaining consortship than previously assumed. It provides new insight into understanding female adaptive strategies to male strategies by forming consortships in multimale–multifemale primate species when males could not identify female''s fertile phase accurately.     

Reproductive success in relation to dominance rank in the absence of prime-age males in Barbary macaques

In some primate species dominance rank of males is correlated with reproductive success, whereas in other species this relationship is inconsistent. Barbary macaques (Macaca sylvanus) live in a promiscuous mating system in which males are ranked in a dominance hierarchy that influences their access to females. High-ranking males usually monopolize fertile females during their estrous period and show increased mating activities. Subadult males generally rank below adult males. For Barbary macaque females in the Gibraltar colony, there was no correlation between dominance status and reproductive success. Paternity data for 31 offspring collected over four consecutive breeding seasons were used to test whether male social rank was associated with reproductive success and whether reproductive success was mainly confined to a small number of males. Genetic variation was assessed using 14 microsatellite markers for a dataset of 127 individuals sampled in all five social groups of the Gibraltar colony. Paternity analysis was conducted for offspring in one social group only, where all in-group males were sampled. Eighty-three percent of the offspring could be assigned to an in-group candidate father; none of the extra-group males appeared to have sired an infant. Male dominance rank was not found to contribute to the observed variation in male reproductive output. Fifty-nine percent of the offspring was sired by two low-ranking males, whereas the two top-ranking males sired one-fifth. A highly significant correlation was found for male age and dominance rank. Reproductive success of subadult males might be explained by the gap in the age distribution of male group members. These missing prime males are usually regarded as serious competitors for older males. Subadult males may have gained easier access to females in their absence. In addition, the presence of inbreeding avoidance mechanisms, which might also have overpowered possible rank effects, cannot be excluded.     

Social and hormonal mechanisms underlying male reproductive strategies in black howler monkeys (Alouatta pigra)

We investigated the social and hormonal mechanisms underlying male reproductive strategies in two multimale-multifemale groups of black howler monkeys (Alouatta pigra) during a 14-month study in Palenque National Park, Mexico. Fecal glucocorticoid (fGC) and androgen (fA) levels were analyzed for 343 fecal samples collected from 14 males during their presence in the study groups. Neither immigrating males nor resident males that remained in the group had elevated fGC and fA levels during 11 observed male migration events, suggesting that competition over group membership was not associated with variation in the fecal hormonal levels of males. Instead, fGC and fA levels were significantly higher in males who maintained a central position in the group and had almost exclusive access to fertile females than in other resident males. These “central” males were responsible for maintaining close spatial associations and cultivating strong affiliative relationships with cycling, sexually active females but not with noncycling, sexually inactive females. “Noncentral” males did not form strong social relationships with either cycling or noncycling females and had no or very few mating opportunities. Our findings suggest that male black howler monkeys compete nonaggressively by fostering relationships with cycling females and that the elevated fGC levels of central males may be indicative of the social challenges involved in their indirect competition.     

雄性短尾猴个体特征与临时配偶关系研究

多雄多雌的灵长类社会群体中,性成熟的雄性和雌性形成临时性的配偶关系（Consortship）是极其显著特征,但这种关系对个体的交配和繁殖成功作用缺少深入研究。本研究以栖息于安徽黄山的短尾猴YA1群为研究对象,采用全事件取样法（All occurrences recording）、目标动物取样法（Focal animal sampling）以及行为取样法（Behavioral sampling method）记录个体间的社会行为、雄性的配偶数量和临时配偶关系的持续时间,对雄性短尾猴临时配偶关系的基本特征与适应策略进行了初步探讨。研究期间,雄性个体的顺位发生替换,在替换前后,处于高顺位的雄性个体始终拥有最多的配偶数量以及形成的临时配偶关系的持续时间最长,并且雄性个体的顺位与临时配偶关系呈正相关关系（顺位变化前：配偶数量：P = 0.010;持续时间：P = 0.014;顺位变化后：配偶数量：P = 0.032;持续时间：P = 0.035）;雄性个体的年龄与临时配偶关系无显著相关性（配偶关系：P = 0.150;持续时间：P = 0.511）;雄性个体在群体中生活的时间与临时配偶关系呈显著正相关（配偶数量：P = 0.034;持续时间：P = 0.023）;雄性个体的社会关系与临时配偶关系呈显著正相关（顺位变化前：配偶数量,P = 0.013;持续时间,P = 0.001;顺位变化后：配偶数量,P < 0.001;持续时间,P = 0.003）。研究结果表明：雄性个体的顺位、在群体中生活时间以及社会关系对临时配偶的形成起主要作用,这为进一步阐明雄性行为策略与临时配偶关系提供新的科学依据。     

Noninvasive paternity assignment in Gombe chimpanzees

The relative success of chimpanzee male mating strategies, the role of male dominance rank and the success of inbreeding avoidance behaviour can only be assessed when paternities are known. We report the probable paternities of 14 chimpanzees included in a long‐term behavioural study of chimpanzees (Pan troglodytes schweinfurthii) at Gombe National Park, Tanzania. DNA samples were collected noninvasively from shed hair and faeces and genotyped using 13–16 microsatellite loci characterized in humans. All 14 offspring could be assigned to fathers within the community. While there is a positive relationship between male rank and reproductive success, we demonstrate that a range of male mating strategies (possessiveness, opportunistic mating and consortships) can lead to paternity across all male ranks. Several adult females were at risk of breeding with close male relatives. Most successfully avoided close inbreeding but in one case a high‐ranking male in the community mated with his mother and produced an offspring. In contrast to recent data on chimpanzees (P. t. verus) from the Taï forest, Côte d’Ivoire, no evidence of extra‐group paternity was observed in our study. Reanalysis of Taï data using a likelihood approach casts doubt on the occurrence of extra‐group paternity in that community as well.     

Spacing pattern in a social group of stray cats: effects on male reproductive success

Reproductive consequences of male spacing patterns have received relatively little attention in nonterritorial mammals, in particular in group-living species, where most studies have focused on the relation between social rank and reproductive success. We investigated the effects of spacing pattern on male reproductive success within a social, nonterritorial, promiscuous population of stray cats, Felis catus. Male home ranges overlapped home ranges of many females, consistent with a promiscuous mating system. Furthermore, males with the largest home ranges included the most female home ranges; they successfully reproduced with these females and had the highest reproductive success. Home range size predicted male reproductive success even when controlling for the effect of social rank. However, males also reproduced with females whose home range did not overlap their home range, suggesting that males can make quick excursions outside their home range to find new mating opportunities. We conclude that, in group-living situations, a male's ability to maintain a large home range may be one of the principal causes of variation in mating success in the stray cat.     

Reproductive strategies of the orang-utan: New data and a reconsideration of existing sociosexual models

Recent field data indicate that MacKinnon’s model of the orang-utan’s sexual and agonistic activity needs to be revised. In this model, male reproductive activity is concentrated in an extended phase of subadulthood and in early adulthood. According to this model, the role of older adult males is primarily that of range guardian, and in that role they would ensure that the offspring they had generated earlier would have safe access to food resources. This study presents cases suggesting that subadult males, even though sexually active, may have low reproductive success. In previous studies adult males were shown to display less sexual initiative than subadult males. In this study an adult male was at times involved infrequent mating activity in response to proceptive activity of females in the course of consortship. This adult male proved to be a successful breeder, thus refuting the hypothesis of adult male sterility. The female is most likely to conceive through cooperative mating in lengthy consortships with the dominant resident adult male. We hypothesize that the extended subadult phase represents a submissive strategy, allowing subadult males to remain in the home range of adult males but with minimal reproductive success.